Fallback to LUT-less tonemapping if compiled without tonemapping_luts

[yyogo]

What problem does this solve or what need does it fill?

Programs compiled without default features (specifically without tonemapping_luts) are now broken in runtime when not explicitly specifying a tone mapping method. This is especially confusing when migrating from pre-0.11 and is hard to figure out from the migration guide.

What solution would you like?

When using a tone mapping method that requires LUTs, but compiled without LUTs, write a warning and fall back to a different tone mapping method (or disable tone mapping altogether).

What alternative(s) have you considered?

• Add a tonemapping_fallback option that only includes LUT-less options.
• Add a Tonemapping::TonyMcMapfaceWithFallback variant as the new default, and have it fallback to ReinhardLuminance
• Generate a compile-time warning or error when compiling without LUTs and choosing a tonemapping that requires it
• Do nothing, make users fix their code, document this in the migration guide.

Additional context

• Ran into this when trying to migrate bevy_mod_raycast to the new version and had the examples break.
• Why is my game all purple/magenta In bevy 0.11? #9100

[yyogo]

Duplicate of #9098; closing